Method of cartoning

ABSTRACT

A package is described wherein the contents are hermetically sealed in an inner lining of moisture resistant flexible sheeting material, which is wholly contained in a closed and sealed container of a substantially rigid material, such as boxboard, and yet the flexible sheeting initially constituted a layer sealed over the entire area of the board by means of a thermoplastic coating such as a microcrystalline wax. The lining remains sealed over a substantial area of the board after completion of the package. The package is rectangular and formed from a single unitary blank, the ends of the container being closed by flaps that have been severed from one another and, over the major portion of their area, detached from the inner lining by the heating of the thermoplastic coating which is then absorbed in the boxboard material. The inner lining is sealed at each end by means of fin seals with web-gusseted ends. These are created by inwardly folding the ends of the container before the flaps are severed from one another, this initial folding involving gusset folding and the subsequent folding, after the severance of the flaps, being that of ordinary dust flaps and cover flaps. The fin seals are heat sealed when the heat is applied to strip the neighboring boxboard from the flexible material.

United States Patent [72] Inventor Stanley Milton Silver 10 BlenheimStreet, London, W. 1, England [21] Appl. No. 855,283

[22] Filed Sept. 4,1969 [45] Patented May 4, 1971 [32] Priority Sept.17,1968 [33] GreatBritain [31] 44074/68 [54] METHOD OF CARTONING 8Clains, l1 DrawingFigs. 52 use: ..1" 53/27, 53/175, 53/284, 93/36(MM),93/3601, 93/84(TW) [51] lnt.Cl. ..B65b 11/58, B3 lb 7/60, 1331b 49/02[50]. FieldofSearch 93/36 (MM), 36.01, 36(.06), 36.6, 58 (ST), 84 (TW);53/27, 175, 284

[56] ReferencesCited UNITED STATES PATENTS 734,224 7/1903 Duhring 53/1751,277,928 9/1918 l-lelson 53/284 2,202,213 5/ 1940 Lindholm... 53/284X2,329,311 9/1943 Waters 53/175X 3,411,694 11/1968 Silver 93/36.01X3,425,324 2/1969 Becker 93/36.01

3,481,098 12/1969 Sherrill 53/27X 3,513,618 5/1970 Woodruff 53/27Primary Examiner-Wayne A. Morse. .lr.

Artorney'-Larson, Taylor & Hinds means of a thermoplastic coating suchas a microcrystalline wax. The lining remains sealed over a substantialarea of the board after completion of the package. The package isrectangular and formed from a single unitary blank, the ends of thecontainer being closed by flaps that have been severed from one anotherand, over the major portion of their area, detached from the innerlining by the heating of the thermoplastic coating which is thenabsorbed in the boxboard material. The inner lining is sealed at eachend by means'of fin seals with web-gusseted ends. These are created byinwardly folding the ends of the container before the flaps are severedfrom one another, this initial folding involving gusset folding and thesubsequent folding, after the severance of the flaps, being that ofordinary dust flaps and cover flaps. The fin seals are heat sealed whenthe heat is applied to strip the neighboring boxboard from the flexiblematerial.

PATENTEDHAY 4197: 3577.699

sum 2. OF 6 PATENTED MAY 4 I97! SHEET 0F 6 PATENTEDINAY 4 Ian 3577.699SHEETS 0F 6 PIATENTYED m 4m snmsore FIG.6.

FIG .7'.

METHOD or CARTONING This invention relates to the manufacture ofpackages such as carton from board material, usually in the form ofthick paper or card.

Prior methods have various disadvantages where it is desired to providean inner lining of impervious material. For instance, there isdifiiculty in using soft plastic sheeting, or in some cases thenecessity of using a rather thick plastic sheeting. Some of thesedisadvantages were overcome by the invention of my previous U.S. Pat.No. 3,41 1,694.

I have now devised a method which overcomes these various disadvantagesand yields in a simple and very economical manner a carton having acompletely sealed lining formed of the laminated sheeting and the boardsupport of the whole carton lies wholly outside the whole of the saidsheeting.

In the present invention the end of the carton is first temporarilyclosed by folding in the form of the laminated board as uncut scoredpanels including web-gussets and having a fin extension composedentirely of the laminated board, then by applying heat to the end panelsthe inner sheeting is heatsealed and released from the board supportwhich is thereby unfolded whereafter the stripped portions of the boardsupport are refolded. Preferably the stripped portions of the boardsupport are severed before being refolded to form flaps which may beadhered to each other in the conventional manner. As is well known inthe art, a web-gusset is formed by folding triangular-shaped flaps whichare usually joined to each other.

Preferably the first temporary closing is done by outfolding, then byapplying the heat the wax is melted on the outer folds while the innersheeting is being heat-sealed, and then the board support which isthereby stripped from at least a portion of each of the web-gussets isopened away from the stripped and sealed inner sheeting. The strippedboard support is then preferably cut to form rectangular flaps which arethen folded down again in the conventional manner and stuck together.

Preferably the heat applied to the first temporarily closed end of thecarton should be insufficient to strip the inner sheeting on theundermost part of the web-gussets because this has the advantage thatwhen the end is finally closed the inner sheeting will be better held inposition.

The following Example illustrates the invention.

FIG. 1 is a plan of a scored blank to be formed into a carton,

FIG. 2 is a cross section through a portion of a blank such as that ofFIG. 1, the section being on a slightly exaggerated scale,

FIGS. 3, 4, a and 5b show a series of different stages in the formationof cartons from blanks as they travel along a series of paths in amachine,

FIGS. 6, 7, 8 and 9 are end views showing stages in the formation of acarton as it travels along the paths of FIGS. 3 and FIG. is aperspective view of a carton at a further stage in its formation.

As shown in FIG. 2 the laminated board comprises an outer layer 1 of theboard support having sufficient porosity to absorb a low-viscositymolten wax. In contact with the board is a layer of microcrystalline wax2, which may be blended with the cheapest grades of paraffin. Paraffinis a cheap material and is a common additive to microcrystalline wax,though its presence does not contribute to adhesiveness. In factparaffin, when heated beyond a critical temperature, acquires an almostwaterlike fluidity. Thus, for the present lamination it acts to reducethe adhesiveness of the wax, control viscosity and reduce cost. In somecases it is possible to blend a microcrystalline wax blend with aheavier viscosity additive such as Elvax (a Dupont Trade Mark).

In contact with the wax layer is a sheeting material 3 which may be ametal foil (e.g. aluminum) or a heat-sealable material such aspolythene, PVDC or a polyester. When the sheeting is not alieat-sealable material, a coating or film 4 having thermoplasticadhesive characteristics is added. The layer 4 may be a film ofheat-sealable polythene, a heat-seal lacquer, or a hot melt which hasbeen extruded onto the metal foil. The thermoplastic sheeting 3 or, whenthe sheeting 3 is not thermoplastic, the additional layer 4, should havea higher melting temperature than the microcrystalline wax layer.

The layers 1, 2, 3, 4 are coextensive, that is to say they all extendover the entire area of the blank. The sheeting 3 may be any suitablesheeting material resistant to the passage of fluid, fluent or migratingsolids or pastes or gases.

The blank of FIG. 1 is one which can be folded as a webgusset eitherinwards or, as preferred, outwards. The blank has a longitudinal sealingflap 5 for the carton side seam. A back panel 6 for the carton isconnected to a side panel 7 which, in turn, is connected to a face panel8 connected to a side panel 9. The single broken lines in the FIG.indicate scorings or creasings for inward folding. Lines 10, 11, 12, 13represent scores which run from opposite edges of the blank to foldlines 36, 36a. The gussets are 14 and 14a. The lines 10, 11, 12, 13represent cuts that only partially penetrate the material. The doublebroken lines represent outward folding creases.

In forming the cartons the blanks are fed in series in the direction ofan arrow 19 (FIG. 3) to a position A on a track 18 along which theblanks are fed continuously and uniformly by means of clips on anendless chain (not shown). On reaching position B the sealing flap 5 isbent forward to break the fold at a crease 15; and a fold along a crease16, between the side panel 7 and face panel 8, is initiated. On reachingposition C, the fold along the crease 16 is increased and a fold on acrease 17, between the face panel 8 and side panel 9, is initiated. Onreaching position D, the sealing flap 5 and the side panel 9 have beenbrought parallel to one another with a preliminary heating device 20between them. Then the folded blank proceeds through positions E, F, Gin which the sealing flap 5 and side panel 9 are in contact with oneanother while passing between two heating devices 21, 22.

The actual folding of the blank as it proceeds along the track 18 iseffected by guide rails 23, 24, 25, 26 (FIG. 6) which are curved so asto fold the blank in the required way during its progress. In practicethe spacing between the positions may be greater than is shown in FIG.3, which is obviously only schematic. The heating device 22 is a highcapacity device and the device 21 has a much lower capacity because theheat required on the front side, i.e. on the side panel 9, may be asmuch as 200 F. lower than that on the other side. The purpose of thisheating is two-fold. Firstly, to seal together the thermoplastic facesof the barrier sheeting 3, where these are in contact close to the loweredges of the sealing flap 5 and side panel 9. Secondly to delaminate thesheeting 3 from the lowermost area of the side panel 9 by causing themicrocrystalline wax 2 to melt and be absorbed by the board support 1.High heat high heat and pressure are required along the sealing flap 5to effect the thermoplastic sealing. The heater 21 on the other side maybe a series of metal rolls extending upwards above the heater 22 andreceiving their heat only from being in close proximity to the heater22. To make a satisfactory heat-seal bond, pressure is required as wellas instant cooling. The bond is completed when the folded blank reachesposition II. The organization of the vertical and horizontal locationsalong the track 18 in such as to make it easy to effect sizechangeovers. The major processing facilities are always kept in the sameposition at the bottom, irrespective of the size of the blank. If alarger blank is to be seamed than that shown, only the guide rails 23,24, 25, 26 which are performing elementary ploughing functions need tobe repositioned. The sealing of the flap 5 to the panel 9 includes thesealing of small gusset elements 14a, 37a and fin elements 40a (FIG. 1)to corresponding portions of gussets 14, 37 and fins 40 at the oppositeedge of the blank.

The folded blank is next transferred from position l-I through positionI (FIG. 4) to another straight line continuousconveyor that carries thefolded blank through a series of positions J to O. In passing throughposition J the opening out of the folded blank has been initiated, thelower part of the side panel 9 being separated from the barrier sheeting3. In position K this movement has proceeded to such an extent that thesaid part of the panel 9 now projects horizontally beyond the back panel6 as shown in FIG. 7. This opening out of the folded blank is effectedby guide rails 27, 28, 29, 30, 31 and a guide rail 32. The mechanicalaction required to strip the loosened sheeting 3 from the board supportis produced by the pivoting action of the rail 28. Thus, the lap-sealededges of the.

sheeting 3 cause the delaminated portion of this sheeting to extend fromthe back panel 6 to the side panel 9 somewhat as shown at 33 in FIG. 7.The projecting portion of the side panel 9 is presented to aconventional adhesive applicator 34. The stripped board has now beenpermeated with wax, the preferred adhesive to be dispensed by theapplicator 34 is hot melt.

As the folded carton continues through the position L to the position M,the pivoting action initiated by the rail 28 continues so as to fold theblank into a substantially flat condition as shown in FIG. 8. The rail31 now brings the interior surface of the panel 9 and its adhesivecoating into adhesive contact with the side seam sealing panel 5.

An alternative method of bringing the sealing panel into contact withthe side panel 9 when the blank has reached the stage of FIG. 7,consists in folding the panel 5 inwardly along the crease line so thatcontact between the panels 5 and 9 is automatically efi'ected when theblank assumes its correct tubular form of rectangular section, as atposition 0. FIG. 9 shows an end view corresponding to positioned 0.

At position P the endfolding is initiated. This initial folding consistsin turning end-panels 34 inwards about creases 35 (FIG. 1), the gussetsl4 outwards about creases 36, gussets 37 inwards about creases 38 andfins 39, 40 outwards about creases 41, 42.

The gusset outfolding is then completed at one end which is to be thebottom end of the carton as it appears at position Q (FIG. 5A). Thisresults in the gussets 14 at the lower end (as shown in position Q)being folded horizontally outwards with the associated gussets 37 sealedto their upper faces. The corresponding fins 40 are folded in half atcreases 43 with the two halves sealed together and the fins 39 aresealed together so as to provide a single straight fin seal runningbetween the tips of the folded gussets. This arrangement can be seenclearly at the top end in positions V, W, X. The heating for effectingthe sealing of the fins and the gussets results in the microcrystallinewax in the fins and gussets 37 being absorbed by the board support sothat these parts are delaminated. The gussets 14 are sufficientlyprotected from the heat by the gussets 37 for these not to bedelaminated.

In passing through positions R, S, T, the carton is filled. As it thenpasses through positions U, V, W, X the top is closed and sealed in theway already described for the bottom.

The next state which is not indicated in FIG. 5A, 5B but which occursbetween positions X and Y is shown in FIG. 10. It consists in openingthe board support part of the carton at its ends once more, whileleaving the contents sealed in the bag constituted by the sheet material3. This is efiected by forcing the gussets 14, at each end, back intoalignment with the side panels 7, 9. The result is that each gussetbecomes substantially coplanar with its two associated gussets 37 oncemore, as shown in FIG. 10. As explained above the gussets 14 stilladhere to the sheeting 3, but the end panels 34, gussets 37 and fins 39,40 are delaminated, so that the sheeting layer remains sealed along afin 43, which is stripped from the board parts of the fins 39, 40 andextends between the centers of the parts 40.

The ends of the sealed sheeting layer are well spaced away from thecomers between the end panels 34 and gussets 37. This enables a suitableknife mechanism to be used to cut these corners down as far as thecreases 35, 36, so as to provide four separate flaps 44, 45, 46, 47 ateach end, as shown at positions Y, and Z.

On reaching position AA the side panel flaps 44, 46 have been folded in.This automatically tucks in the sealed sheeting 3 of the gussets andfins 43. At position BB, the closure flaps 45 are being folded in andadhesive is applied to the closure flaps 47. At position CC the closureflaps 47 are being folded in for sealing to the flaps 45. At DD thecompleted and sealed carton is being passed on for stacking and packing.

For the sheeting layer 3 a thermoplastic film having little or no shrinkcharacteristics is preferred. The films orientation should preferably belongitudinal, and it should have been manufactured with minimumstretching. The wax layer should be such that when it is melted byheating it should have a sufficiently low viscosity to enable it topenetrate the board easily. If any is left on the surface it should benonblocking.

The board support may be typical boxboard, though boards having a higherdegree of bulk or increased porosity are preferred because they havegreater wax-absorbing properties.

I claim:

1. The method of permanently closing the end of a rectangular tubularpackage formed of a board material and having an inner sheeting bytaking a laminated material formed of a board support to which islaminated the sheeting having a heat-adhesive surface and the sheetingbeing attached to the support by an adhesive coating having thepotential to permit the sheeting to strip from the support by theapplication of local heat, folding the blank to bring togetherface-to-face two areas thereof for joining the sheeting surfaces to formthe required lining and applying sufficient heat both to effect suchjoining and to strip the sheet-lining, characterized in that joinedscored panels at the end of the package are first temporarily closed byfolding to form web-gussets having a fin extension, the scored panelsbeing composed entirely of the laminated board, then by applying heat tothe end panels the inner sheet-lining is heat-sealed and also releasedfrom the board which is then unfolded, whereafter the stripped portionsof the board-support are refolded to complete the end closure.

2. The method according to claim 1, characterized in that, before thefinal closure, the stripped and unfolded portions of the board supportare cut to form rectangular flaps.

3. A method according to claim 1, in which both ends of the package arepermanently closed in the same way.

4. A method according to claim 1, characterized in that the package isformed with a side seam that continues into the web-gussets on one side,by bringing the sheeting on a sealing flap into contact face-to-facewith the sheet-lining on a side panel, heating the contacting layers ofsheeting so as to join them along areas adjacent the free areas of thesealing flap and side panel and to enable the sheeting to be strippedfrom the board support of the side panel, stripping the sheeting fromthe said board support, applying adhesive to the stripped portion of theboard support and folding the stripped portion of the board support sothat it overlaps and adheres to the outer, board support, surface of thesealing flap.

5. The method of forming a package composed of a substantially rigidmaterial such as boxboard to the whole of one face of which amoisture-resistant flexible sheeting material has been adhered by meansof a thermoplastic coating such as microcrystalline wax, which comprisesthe steps of forming the rigid material into rectangular tubular formwith the sheeting material inside, closing each end of the tubular formfilling before completing the closing of the second end, each closingprocedure comprising forming webgussets on each side and a fin-extensionextending between and overlying the web-gussets, so that the package hasa complete inner lining of the flexible sheeting material containedwholly within the whole of the rigid material, and then stripping, ateach web-gusseted end, the major part of the flexible sheeting materialfrom the rigid material, heat sealing the fin extension of the lining,folding the rigid material in the form of flaps wholly outside thelining, and adhering the respective end flaps to one another.

6. A method according to claim 5, characterized in that the flapsconstituting extensions of the main walls of the rectangular tubularpackage are severed from one another subsequently to the heat sealingbut before they are folded wholly outside the lining.

7. A method of forming a package composed of a substantially rigidmaterial such as boxboard to the whole of one face of which amoisture-resistant flexible sheeting material has been adhered by meansof a thermoplastic coating such as microcrystalline wax, which comprisesforming the rigid material into a rectangular tubular form with thesheeting material inside and with a side seam by the steps of bringingthe sheeting on a sealing flap into contact face-to-face with thesheet-lining on a side panel, heating the contracting layers ofsheet-lining so as to join them along areas adjacent the free area ofthe sealing flap and side panel and to enable the sheeting to bestripped from the board support of the side panel,

1. The method of permanently closing the end of a rectangular tubularpackage formed of a board material and having an inner sheetinG bytaking a laminated material formed of a board support to which islaminated the sheeting having a heat-adhesive surface and the sheetingbeing attached to the support by an adhesive coating having thepotential to permit the sheeting to strip from the support by theapplication of local heat, folding the blank to bring togetherface-to-face two areas thereof for joining the sheeting surfaces to formthe required lining and applying sufficient heat both to effect suchjoining and to strip the sheet-lining, characterized in that joinedscored panels at the end of the package are first temporarily closed byfolding to form web-gussets having a fin extension, the scored panelsbeing composed entirely of the laminated board, then by applying heat tothe end panels the inner sheet-lining is heat-sealed and also releasedfrom the board which is then unfolded, whereafter the stripped portionsof the board-support are refolded to complete the end closure.
 2. Themethod according to claim 1, characterized in that, before the finalclosure, the stripped and unfolded portions of the board support are cutto form rectangular flaps.
 3. A method according to claim 1, in whichboth ends of the package are permanently closed in the same way.
 4. Amethod according to claim 1, characterized in that the package is formedwith a side seam that continues into the web-gussets on one side, bybringing the sheeting on a sealing flap into contact face-to-face withthe sheet-lining on a side panel, heating the contacting layers ofsheeting so as to join them along areas adjacent the free areas of thesealing flap and side panel and to enable the sheeting to be strippedfrom the board support of the side panel, stripping the sheeting fromthe said board support, applying adhesive to the stripped portion of theboard support and folding the stripped portion of the board support sothat it overlaps and adheres to the outer, board support, surface of thesealing flap.
 5. The method of forming a package composed of asubstantially rigid material such as boxboard to the whole of one faceof which a moisture-resistant flexible sheeting material has beenadhered by means of a thermoplastic coating such as microcrystallinewax, which comprises the steps of forming the rigid material intorectangular tubular form with the sheeting material inside, closing eachend of the tubular form filling before completing the closing of thesecond end, each closing procedure comprising forming web-gussets oneach side and a fin-extension extending between and overlying theweb-gussets, so that the package has a complete inner lining of theflexible sheeting material contained wholly within the whole of therigid material, and then stripping, at each web-gusseted end, the majorpart of the flexible sheeting material from the rigid material, heatsealing the fin extension of the lining, folding the rigid material inthe form of flaps wholly outside the lining, and adhering the respectiveend flaps to one another.
 6. A method according to claim 5,characterized in that the flaps constituting extensions of the mainwalls of the rectangular tubular package are severed from one anothersubsequently to the heat sealing but before they are folded whollyoutside the lining.
 7. A method of forming a package composed of asubstantially rigid material such as boxboard to the whole of one faceof which a moisture-resistant flexible sheeting material has beenadhered by means of a thermoplastic coating such as microcrystallinewax, which comprises forming the rigid material into a rectangulartubular form with the sheeting material inside and with a side seam bythe steps of bringing the sheeting on a sealing flap into contactface-to-face with the sheet-lining on a side panel, heating thecontracting layers of sheet-lining so as to join them along areasadjacent the free area of the sealing flap and side panel and to enablethe sheeting to be stripped from the board support of the side panel,strippIng the sheeting from the said board support, applying adhesive toeither the stripped portion of the board support or the outer, boardsupport of the sealing flap and folding the stripped portion of theboard support so that it overlaps and adheres to the outer, boardsupport surface of the sealing flap, filling, folding and sealing theends of the tubular form to provide a closed and sealed package.
 8. Amethod according to claim 1, in which the adhesive coating is absorbedby the board material when the sheeting is heated.